diff --git a/django/utils/dateparse.py b/django/utils/dateparse.py
index 8d08b7d1d3..a037758784 100644
--- a/django/utils/dateparse.py
+++ b/django/utils/dateparse.py
@@ -29,7 +29,7 @@ datetime_re = re.compile(
 standard_duration_re = re.compile(
     r'^'
     r'(?:(?P<days>-?\d+) (days?, )?)?'
-    r'((?:(?P<hours>-?\d+):)(?=\d+:\d+))?'
+    r'((?:(?P<hours>-?\d+):)(?=-?\d+:-?\d+))?'
     r'(?:(?P<minutes>-?\d+):)?'
     r'(?P<seconds>-?\d+)'
     r'(?:\.(?P<microseconds>\d{1,6})\d{0,6})?'
